The Mawson’s Huts Historic Site at Cape Denison in the AAT is Australia’s oldest and arguably most significant historic heritage site in Antarctica. At the time of their construction, more than 100 years ago, the huts were built to last only a few years. It was never anticipated that they would still be standing a century later and considered a valuable part of Australia’s Antarctic heritage.
The building materials are vulnerable to deterioration, and the natural elements—wind, weather, frost, ice and melt water—threaten the integrity of the buildings and structures. Corrosion, fungal growth, wind and snow loads, exposure to ultraviolet radiation, the freeze–thaw cycle, and high relative humidity inside the main hut also affect the conservation of structures and artefacts (Lazer 2006).
The Mawson’s Huts Historic Site Management Plan provides guidance for the protection and conservation of the site buildings and artefacts. The AAD works closely with the Mawson’s Huts Foundation to determine conservation priorities and methods to appropriately manage the site.
On the subantarctic islands, artefacts associated with 19th century sealing activities remain. The maritime climate promotes corrosion of metal artefacts, and wooden items are abraded by windborne sand and salt particles. Disturbance by wildlife, land erosion and slippage are also potential problems (Vincent & Grinbergs 2002, Clark 2003, Vincent 2004), as are erosion and exposure of artefacts, and volcanic and seismic activities. Seismic activity has been identified as a specific threat to structures on Macquarie Island, although most of the research expedition buildings have been built to withstand tremors (Lazer 2006).
Heard Island is a long way from continental Australia, and caring for the components of historic heritage on the island is an enormous challenge. The cultural heritage of Heard Island is therefore conserved through a process of managed decay. This is a pragmatic management option, which acknowledges the practical impossibility of conserving all elements of the cultural environment in a remote area where access is extremely limited (Vincent & Grinbergs 2002, Lazer 2006). Permitted visits are very infrequent and tend to be restricted to the short summer. The management plan states that heritage values, such as buildings, are in a greatly deteriorated state and have been in such a state for a long time, and are permitted to disintegrate under the influences of weather and climate. However, the exposed asbestos requires management, because it poses a threat to the natural environmental and a safety risk for people visiting the site. There are several sealers’ graves in the south-eastern part of the island, not far from a large king penguin (Aptenodytes patagonicus) colony. The vegetation cover is dense, and continues to engulf and cover the old graves.
A specific risk to Heard Island is the changing coastline. For example, wooden oil barrels that were left by sealers at Oil Barrel Point have disappeared steadily during the past few decades as they have eroded out of the beach cliff (Lazer & McGowan 1990). Less than a quarter of those recorded in the 1980s are still in place.
The AAD liaises closely with vessel operators known to be interested in visiting the island to advise them of authorisation requirements. Given Heard Island’s remote location, however, it is possible that some unauthorised visits could occur and that activities that would otherwise require a permit, such as entering the Heritage Zone or collecting materials from the island, could be done without the Australian Government being aware.